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Compact Muon Solenoid
LHC, CERN

CMS-HIG-22-007 ; CERN-EP-2023-284
Search for exotic decays of the Higgs boson to a pair of pseudoscalars in the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau\mathrm{b}\mathrm{b} $ final states
Submitted to Eur. Phys. J. C
Abstract: A search for exotic decays of the Higgs boson (H) with a mass of 125 GeV to a pair of light pseudoscalars $ a_{1} $ is performed in final states where one pseudoscalar decays to two b quarks and the other to a pair of muons or $ \tau $ leptons. A data sample of proton-proton collisions at $ \sqrt{s}= $ 13 TeV corresponding to an integrated luminosity of 138 fb$ ^{-1} $ recorded with the CMS detector is analyzed. No statistically significant excess is observed over the standard model backgrounds. Upper limits are set at 95% confidence level (CL) on the Higgs boson branching fraction to $ \mu\mu\mathrm{b}\mathrm{b} $ and to $ \tau\tau\mathrm{b}\mathrm{b} $, via a pair of $ a_{1} $s. The limits depend on the pseudoscalar mass $ m_{a_{1}} $ and are observed to be in the range (0.17-3.3) $ \times $ 10$^{-4} $ and (1.7-7.7) $ \times $ 10$^{-2} $ in the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau\mathrm{b}\mathrm{b} $ final states, respectively. In the framework of models with two Higgs doublets and a complex scalar singlet (2HDM+S), the results of the two final states are combined to determine model-independent upper limits on the branching fraction $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to \ell\ell\mathrm{b}\mathrm{b}) $ at 95% CL, with $ \ell $ being a muon or a $ \tau $ lepton. For different types of 2HDM+S, upper bounds on the branching fraction $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ are extracted from the combination of the two channels. In most of the Type II 2HDM+S parameter space, $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ values above 0.23 are excluded at 95% CL for $ m_{a_{1}} $ values between 15 and 60 GeV.
Figures & Tables Summary References CMS Publications
Figures

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Figure 1:
The distributions of leading and subleading (upper) muon $ p_{\mathrm{T}} $ and (lower) b jet $ p_{\mathrm{T}} $ in the selected events. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 1-a:
The distributions of leading and subleading (upper) muon $ p_{\mathrm{T}} $ and (lower) b jet $ p_{\mathrm{T}} $ in the selected events. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 1-b:
The distributions of leading and subleading (upper) muon $ p_{\mathrm{T}} $ and (lower) b jet $ p_{\mathrm{T}} $ in the selected events. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 1-c:
The distributions of leading and subleading (upper) muon $ p_{\mathrm{T}} $ and (lower) b jet $ p_{\mathrm{T}} $ in the selected events. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 1-d:
The distributions of leading and subleading (upper) muon $ p_{\mathrm{T}} $ and (lower) b jet $ p_{\mathrm{T}} $ in the selected events. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 2:
The $ p_{\mathrm{T}} $ distributions of the (left) dimuon systems and (right) di-b-jet system. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized to using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 2-a:
The $ p_{\mathrm{T}} $ distributions of the (left) dimuon systems and (right) di-b-jet system. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized to using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 2-b:
The $ p_{\mathrm{T}} $ distributions of the (left) dimuon systems and (right) di-b-jet system. The uncertainty band in the lower panel represents the limited size of the simulated samples together with a 30% uncertainty in the low-mass DY cross section. Simulated samples are normalized to using the corresponding theoretical cross sections. To evaluate the normalization of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta = $ 2.

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Figure 3:
The distribution of $ \chi_{\mathrm{b}\mathrm{b}} $ versus $ \chi_{\mathrm{H}} $ as defined in Eq. (1) for (left) simulated background processes and (right) the signal process with $ m_{a_{1}} = $ 40 GeV. The contours indicate lines of constant $ \chi_\text{tot}^2 $. The gray scale represents the expected yields in data. To evaluate the yield of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta= $ 2.

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Figure 3-a:
The distribution of $ \chi_{\mathrm{b}\mathrm{b}} $ versus $ \chi_{\mathrm{H}} $ as defined in Eq. (1) for (left) simulated background processes and (right) the signal process with $ m_{a_{1}} = $ 40 GeV. The contours indicate lines of constant $ \chi_\text{tot}^2 $. The gray scale represents the expected yields in data. To evaluate the yield of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta= $ 2.

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Figure 3-b:
The distribution of $ \chi_{\mathrm{b}\mathrm{b}} $ versus $ \chi_{\mathrm{H}} $ as defined in Eq. (1) for (left) simulated background processes and (right) the signal process with $ m_{a_{1}} = $ 40 GeV. The contours indicate lines of constant $ \chi_\text{tot}^2 $. The gray scale represents the expected yields in data. To evaluate the yield of the signal, SM Higgs boson cross sections are multiplied by the $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ value that is calculated in the Type III model with $ \tan\beta= $ 2.

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Figure 4:
Signal ($ m_{a_{1}}= $ 40 GeV) versus background efficiency for different thresholds on $ \chi_\text{tot}^2 $ (gray) and $ \chi_\mathrm{d}^2 $ (red) variables. The black star indicates signal efficiency versus that of background for the optimized $ \chi_\mathrm{d}^2 $ requirement.

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Figure 5:
Pre-fit distributions of the DNN score for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel divided into events with one (left) or at least two (right) b jets. The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%. The lower panel shows the ratio of the observed data to the expected yields. The gray band represents the unconstrained statistical and systematic uncertainties.

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Figure 5-a:
Pre-fit distributions of the DNN score for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel divided into events with one (left) or at least two (right) b jets. The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%. The lower panel shows the ratio of the observed data to the expected yields. The gray band represents the unconstrained statistical and systematic uncertainties.

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Figure 5-b:
Pre-fit distributions of the DNN score for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel divided into events with one (left) or at least two (right) b jets. The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%. The lower panel shows the ratio of the observed data to the expected yields. The gray band represents the unconstrained statistical and systematic uncertainties.

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Figure 6:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 6-a:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 6-b:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 6-c:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 6-d:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 6-e:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 6-f:
The best fit background models for the $ \mu\mu\mathrm{b}\mathrm{b} $ channel together with a 68% CL uncertainty band from the fit to the data under the background-only hypothesis for the (upper left) Low $ p_{\mathrm{T}} $ category, (middle left) VBF category, (middle right) TL category, (lower left) TM category, and (lower right) TT category. For comparison, the signal-plus-background is shown for the (upper right) Low $ p_{\mathrm{T}} $ category for a signal with $ m_{a_{1}} = $ 40 GeV. The expected signal yield is evaluated assuming the SM production of the Higgs boson and a $ \mathcal{B}(a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ as predicted in the Type III 2HDM+S with $ \tan\beta= $ 2. The bin widths depend on statistics, irrelevant for the final fit.

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Figure 7:
Post-fit distributions of $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with exactly one b tagged jet: SR1 (upper left ), SR2 (upper right), and SR3 (lower). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 7-a:
Post-fit distributions of $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with exactly one b tagged jet: SR1 (upper left ), SR2 (upper right), and SR3 (lower). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 7-b:
Post-fit distributions of $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with exactly one b tagged jet: SR1 (upper left ), SR2 (upper right), and SR3 (lower). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 7-c:
Post-fit distributions of $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with exactly one b tagged jet: SR1 (upper left ), SR2 (upper right), and SR3 (lower). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 8:
Post-fit distributions of the $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with at least two b tagged jets: SR1 (left) and SR2 (right). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 8-a:
Post-fit distributions of the $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with at least two b tagged jets: SR1 (left) and SR2 (right). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 8-b:
Post-fit distributions of the $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel signal regions in events with at least two b tagged jets: SR1 (left) and SR2 (right). The shape of the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is indicated assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 9:
Post-fit distributions of the $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel control regions in events with exactly one b tagged jet (left) and at least two b tagged jets (right). The contamination from the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is barely visible assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 9-a:
Post-fit distributions of the $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel control regions in events with exactly one b tagged jet (left) and at least two b tagged jets (right). The contamination from the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is barely visible assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 9-b:
Post-fit distributions of the $ m_{\tau\tau} $ for the $ \mu\hspace{-.04em}\tau_\mathrm{h} $ channel control regions in events with exactly one b tagged jet (left) and at least two b tagged jets (right). The contamination from the $ \mathrm{H}\to a_{1} a_{1} $ signal, where $ m_{a_{1}} = $ 35 GeV, is barely visible assuming $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ to be 10%.

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Figure 10:
Observed and expected upper limits at 95% CL on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to \mu\mu\mathrm{b}\mathrm{b}) $ as functions of $ m_{a_{1}} $. The inner and outer bands indicate the regions containing the distribution of limits located within 68 and 95% confidence intervals, respectively, of the expectation under the background-only hypothesis.

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Figure 11:
Observed and expected 95% CL exclusion limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ in percent, for the (upper left) $ \mu\hspace{-.04em}\tau_\mathrm{h} $, (upper right) $ \mathrm{e}\hspace{-.04em}\tau_\mathrm{h} $, (lower left) $ \mathrm{e}\hspace{-.04em}\mu $ channels, and (lower right) for the combination of all the channels.

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Figure 11-a:
Observed and expected 95% CL exclusion limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ in percent, for the (upper left) $ \mu\hspace{-.04em}\tau_\mathrm{h} $, (upper right) $ \mathrm{e}\hspace{-.04em}\tau_\mathrm{h} $, (lower left) $ \mathrm{e}\hspace{-.04em}\mu $ channels, and (lower right) for the combination of all the channels.

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Figure 11-b:
Observed and expected 95% CL exclusion limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ in percent, for the (upper left) $ \mu\hspace{-.04em}\tau_\mathrm{h} $, (upper right) $ \mathrm{e}\hspace{-.04em}\tau_\mathrm{h} $, (lower left) $ \mathrm{e}\hspace{-.04em}\mu $ channels, and (lower right) for the combination of all the channels.

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Figure 11-c:
Observed and expected 95% CL exclusion limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ in percent, for the (upper left) $ \mu\hspace{-.04em}\tau_\mathrm{h} $, (upper right) $ \mathrm{e}\hspace{-.04em}\tau_\mathrm{h} $, (lower left) $ \mathrm{e}\hspace{-.04em}\mu $ channels, and (lower right) for the combination of all the channels.

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Figure 11-d:
Observed and expected 95% CL exclusion limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $ in percent, for the (upper left) $ \mu\hspace{-.04em}\tau_\mathrm{h} $, (upper right) $ \mathrm{e}\hspace{-.04em}\tau_\mathrm{h} $, (lower left) $ \mathrm{e}\hspace{-.04em}\mu $ channels, and (lower right) for the combination of all the channels.

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Figure 12:
Observed and expected 95% CL upper limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to \ell\ell\mathrm{b}\mathrm{b}) $ in %, where $ \ell $ stands for muons or $ \tau $ leptons, obtained from the combination of the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels. The results are obtained as functions of $ m_{a_{1}} $ for 2HDM+S models, independent of the type and $ \tan\beta $ parameter.

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Figure 13:
Observed and expected 95% CL upper limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ in %, obtained from the combination of the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels. The results are obtained as functions of $ m_{a_{1}} $ for 2HDM+S Type I (independent of $ \tan\beta $), Type II ($ \tan\beta= $ 2.0), Type III ($ \tan\beta= $ 2.0), and Type IV ($ \tan\beta= $ 0.6), respectively.

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Figure 14:
Observed 95% CL upper limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ in %, for the combination of the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels for Type III (left) and Type IV (right) 2HDM+S in the $ \tan\beta \mbox{\textsl{vs.}} m_{a_{1}} $ parameter space. The limits are calculated in a grid of 5 GeV in $ m_{a_{1}} $ and 0.1-0.5 in $ \tan\beta $, interpolating the points in between. The contours corresponding to branching fractions of 100 and 16% are drawn using dashed lines, where 16% refers to the combined upper limit on Higgs boson to undetected particle decays from previous Run 2 results [15]. All points inside the contour are allowed within that upper limit.

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Figure 14-a:
Observed 95% CL upper limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ in %, for the combination of the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels for Type III (left) and Type IV (right) 2HDM+S in the $ \tan\beta \mbox{\textsl{vs.}} m_{a_{1}} $ parameter space. The limits are calculated in a grid of 5 GeV in $ m_{a_{1}} $ and 0.1-0.5 in $ \tan\beta $, interpolating the points in between. The contours corresponding to branching fractions of 100 and 16% are drawn using dashed lines, where 16% refers to the combined upper limit on Higgs boson to undetected particle decays from previous Run 2 results [15]. All points inside the contour are allowed within that upper limit.

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Figure 14-b:
Observed 95% CL upper limits on $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ in %, for the combination of the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels for Type III (left) and Type IV (right) 2HDM+S in the $ \tan\beta \mbox{\textsl{vs.}} m_{a_{1}} $ parameter space. The limits are calculated in a grid of 5 GeV in $ m_{a_{1}} $ and 0.1-0.5 in $ \tan\beta $, interpolating the points in between. The contours corresponding to branching fractions of 100 and 16% are drawn using dashed lines, where 16% refers to the combined upper limit on Higgs boson to undetected particle decays from previous Run 2 results [15]. All points inside the contour are allowed within that upper limit.
Tables

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Table 1:
The electron, muon, and $ \tau_\mathrm{h} p_{\mathrm{T}} $ thresholds in GeV at trigger level for the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels.

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Table 3:
Summary of the categorization requirements in the $ \mu\mu\mathrm{b}\mathrm{b} $ channel. Events in these categories contain two muons and two b jets. As stated in the text, L, M, and T stand for the loose, medium, and tight b tagging criteria, respectively.

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Table 4:
The expected yields for backgrounds and different signal hypotheses in each category of the $ \mu\mu\mathrm{b}\mathrm{b} $ channel.
Summary
A search for an exotic decay of the 125 GeV Higgs boson (H) to a pair of light pseudoscalar bosons (a_{1} ) in the final state with two b quarks and two muons or two $ \tau $ leptons has been presented. The results are based on a data sample of proton-proton collisions corresponding to an integrated luminosity of 138 fb$^{-1}$, accumulated by the CMS experiment at the LHC during Run 2 at a center-of-mass energy of 13 TeV. Final states with at least one leptonic $ \tau $ decay are studied in the $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channel, excluding those with two muons or two electrons. The results show significant improvement, with respect to the earlier CMS analyses at 13 TeV, beyond what is merely expected from the increase in the size of the data sample. A more thorough analysis of the signal properties using a single discriminating variable improves the $ \mu\mu\mathrm{b}\mathrm{b} $ analysis, while the $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ analysis gains from a deep neural network based signal categorization. No significant excess in the data over the standard model backgrounds is observed. Upper limits are set, at 95% confidence level, on branching fractions $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\mu\mu\mathrm{b}\mathrm{b}) $ and $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to\tau\tau{\mathrm{b}}{\mathrm{b}}) $, in the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ analyses, respectively. Both analyses provide the most stringent expected limits to date. In the $ \mu\mu\mathrm{b}\mathrm{b} $ channel, the observed limits are in the range (0.17-3.3) $ \times $ 10$^{-4} $ for a pseudoscalar mass, $ m_{a_{1}} $, between 15 and 62.5 GeV. Combining all final states in the $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channel, limits are observed to be in the range 1.7-7.7% for $ m_{a_{1}} $ between 12 and 60 GeV. By combining the $ \mu\mu\mathrm{b}\mathrm{b} $ and $ \tau\tau{\mathrm{b}}{\mathrm{b}} $ channels, model-independent limits are set on the branching fraction $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} \to \ell\ell\mathrm{b}\mathrm{b}) $, where $ \ell $ stands for muons or $ \tau $ leptons. The observed upper limits range between 0.6 and 7.7% depending on the $ m_{a_{1}} $. The results can also be interpreted in different types of 2HDM+S models. For $ m_{a_{1}} $ values between 15 and 60 GeV, $ \mathcal{B}(\mathrm{H}\to a_{1} a_{1} ) $ values above 23% are excluded, at 95% confidence level, in most of the Type II scenarios. In Types III and IV, observed upper limits as low as 1 and 3% are obtained, respectively, for $ \tan\beta= $ 2.0 and 0.5.
References
1 ATLAS Collaboration Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC PLB 716 (2012) 1 1207.7214
2 CMS Collaboration Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC PLB 716 (2012) 30 CMS-HIG-12-028
1207.7235
3 CMS Collaboration Observation of a new boson with mass near 125 GeV in $ pp $ collisions at $ \sqrt{s} $ = 7 and 8 TeV JHEP 06 (2013) 081 CMS-HIG-12-036
1303.4571
4 F. Englert and R. Brout Broken Symmetry and the Mass of Gauge Vector Mesons PRL 13 (1964) 321
5 P. W. Higgs Broken symmetries, massless particles and gauge fields PL 12 (1964) 132
6 P. W. Higgs Broken symmetries and the masses of gauge bosons PRL 13 (1964) 508
7 G. S. Guralnik, C. R. Hagen, and T. W. B. Kibble Global conservation laws and massless particles PRL 13 (1964) 585
8 P. W. Higgs Spontaneous symmetry breakdown without massless bosons PR 145 (1966) 1156
9 T. W. B. Kibble Symmetry breaking in non-abelian gauge theories PR 155 (1967) 1554
10 G. C. Branco et al. Theory and phenomenology of two-Higgs-doublet models Phys. Rept. 516 (2012) 1 1106.0034
11 A. Djouadi The Anatomy of electro-weak symmetry breaking. II. The Higgs bosons in the minimal supersymmetric model Phys. Rept. 459 (2008) 1 hep-ph/0503173
12 T. Robens and T. Stefaniak Status of the Higgs Singlet Extension of the Standard Model after LHC Run 1 EPJC 75 (2015) 104 1501.02234
13 T. Robens, T. Stefaniak, and J. Wittbrodt Two-real-scalar-singlet extension of the SM: LHC phenomenology and benchmark scenarios EPJC 80 (2020) 151 1908.08554
14 ATLAS Collaboration A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery Nature 607 (2022) 52 2207.00092
15 CMS Collaboration A portrait of the Higgs boson by the CMS experiment ten years after the discovery Nature 607 (2022) 60 CMS-HIG-22-001
2207.00043
16 D. Curtin et al. Exotic decays of the 125 GeV Higgs boson PRD 90 (2014) 075004 1312.4992
17 B. Grzadkowski and P. Osland Tempered Two-Higgs-Doublet Model PRD 82 (2010) 125026 0910.4068
18 A. Drozd, B. Grzadkowski, J. F. Gunion, and Y. Jiang Extending two-Higgs-doublet models by a singlet scalar field - the Case for Dark Matter JHEP 11 (2014) 105 1408.2106
19 S. Ramos-Sanchez The $ \mu $-problem, the NMSSM and string theory Fortschritte der Phys. 58 (2010) 748 1003.1307
20 D. de Florian et al. Handbook of LHC Higgs cross sections: 4. Deciphering the nature of the Higgs sector CERN Report CERN-2017-002-M, 2016
link
1610.07922
21 ATLAS Collaboration Search for Higgs boson decays into a pair of pseudoscalar particles in the $ bb\mu\mu $ final state with the ATLAS detector in $ pp $ collisions at $ \sqrt{s}= $ 13 TeV PRD 105 (2022) 012006 2110.00313
22 ATLAS Collaboration Search for Higgs boson decays into a pair of light bosons in the $ \mathrm{b}\mathrm{b}\mu\mu $ final state in pp collision at $ \sqrt{s} = $ 13 TeV with the ATLAS detector PLB 790 (2019) 1 1807.00539
23 CMS Collaboration Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two muons and two b quarks in pp collisions at 13 TeV PLB 795 (2019) 398 CMS-HIG-18-011
1812.06359
24 CMS Collaboration Search for light bosons in decays of the 125 GeV Higgs boson in proton-proton collisions at $ \sqrt{s}= $ 8 TeV JHEP 10 (2017) 076 CMS-HIG-16-015
1701.02032
25 CMS Collaboration Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two b quarks and two $ \tau $ leptons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV PLB 785 (2018) 462 CMS-HIG-17-024
1805.10191
26 CMS Collaboration HEPData record for this analysis link
27 CMS Collaboration The CMS trigger system JINST 12 (2017) P01020 CMS-TRG-12-001
1609.02366
28 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004
29 T. Sjöstrand et al. An Introduction to PYTHIA 8.2 Comput. Phys. Commun. 191 (2015) 159 1410.3012
30 NNPDF Collaboration Parton distributions from high-precision collider data EPJC 77 (2017) 663 1706.00428
31 J. Alwall, S. de Visscher, and F. Maltoni QCD radiation in the production of heavy colored particles at the LHC JHEP 02 (2009) 017 0810.5350
32 J. Alwall et al. Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions EPJC 53 (2008) 473 0706.2569
33 R. Frederix and S. Frixione Merging meets matching in MC@NLO JHEP 12 (2012) 061 1209.6215
34 J. Alwall et al. The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations JHEP 07 (2014) 079 1405.0301
35 P. Skands, S. Carrazza, and J. Rojo Tuning PYTHIA 8.1: the Monash 2013 Tune EPJC 74 (2014) 3024 1404.5630
36 CMS Collaboration Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements EPJC 80 (2020) 4 CMS-GEN-17-001
1903.12179
37 GEANT4 Collaboration GEANT4--a simulation toolkit NIM A 506 (2003) 250
38 J. Allison et al. Geant4 developments and applications IEEE Trans. Nucl. Sci. 53 (2006) 270
39 CMS Collaboration Measurements of Higgs boson production in the decay channel with a pair of $ \tau $ leptons in proton-proton collisions at $ \sqrt{s}= $ 13 TeV no.~7, 562, 2023
EPJC 83 (2023)
CMS-HIG-19-010
2204.12957
40 P. Nason A New method for combining NLO QCD with shower Monte Carlo algorithms JHEP 11 (2004) 040 hep-ph/0409146
41 S. Frixione, P. Nason, and C. Oleari Matching NLO QCD computations with Parton Shower simulations: the POWHEG method JHEP 11 (2007) 070 0709.2092
42 S. Alioli, P. Nason, C. Oleari, and E. Re A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX JHEP 06 (2010) 043 1002.2581
43 S. Alioli et al. Jet pair production in POWHEG JHEP 04 (2011) 081 1012.3380
44 M. Czakon et al. Top-pair production at the LHC through NNLO QCD and NLO EW JHEP 10 (2017) 186 1705.04105
45 M. Czakon and A. Mitov Top++: A Program for the Calculation of the Top-Pair Cross-Section at Hadron Colliders Comput. Phys. Commun. 185 (2014) 2930 1112.5675
46 M. Botje et al. The PDF4LHC Working Group interim recommendations 1101.0538
47 A. D. Martin, W. J. Stirling, R. S. Thorne, and G. Watt Uncertainties on alpha(S) in global PDF analyses and implications for predicted hadronic cross sections EPJC 64 (2009) 653 0905.3531
48 J. Gao et al. CT10 next-to-next-to-leading order global analysis of QCD no.~3, 033009, 2014
PRD 89 (2014)
1302.6246
49 R. D. Ball et al. Parton distributions with LHC data NPB 867 (2013) 244 1207.1303
50 J. Campbell, T. Neumann, and Z. Sullivan Single-top-quark production in the $ t $-channel at NNLO JHEP 02 (2021) 040 2012.01574
51 PDF4LHC Working Group Collaboration The PDF4LHC21 combination of global PDF fits for the LHC Run III no.~8, 080501, 2022
JPG 49 (2022)
2203.05506
52 K. Melnikov and F. Petriello Electroweak gauge boson production at hadron colliders through $ O(\alpha_s^2) $ PRD 74 (2006) 114017 hep-ph/0609070
53 A. D. Martin, W. J. Stirling, R. S. Thorne, and G. Watt Parton distributions for the LHC --285, 2009
EPJC 63 (2009) 189
0901.0002
54 S. Alioli, P. Nason, C. Oleari, and E. Re NLO Higgs boson production via gluon fusion matched with shower in POWHEG JHEP 04 (2009) 002 0812.0578
55 E. Bagnaschi, G. Degrassi, P. Slavich, and A. Vicini Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM JHEP 02 (2012) 088 1111.2854
56 P. Nason and C. Oleari NLO Higgs boson production via vector-boson fusion matched with shower in POWHEG JHEP 02 (2010) 037 0911.5299
57 G. Luisoni, P. Nason, C. Oleari, and F. Tramontano $ \mathrm{H}\mathrm{W}^{\pm} $/HZ + 0 and 1 jet at NLO with the POWHEG BOX interfaced to GoSam and their merging within MiNLO JHEP 10 (2013) 083 1306.2542
58 H. B. Hartanto, B. Jager, L. Reina, and D. Wackeroth Higgs boson production in association with top quarks in the POWHEG BOX PRD 91 (2015) 094003 1501.04498
59 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017) P10003 CMS-PRF-14-001
1706.04965
60 CMS Collaboration Technical proposal for the Phase-II upgrade of the Compact Muon Solenoid CMS Technical Proposal CERN-LHCC-2015-010, CMS-TDR-15-02, 2015
CDS
61 CMS Collaboration Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s}= $ 13 TeV JINST 13 (2018) P06015 CMS-MUO-16-001
1804.04528
62 CMS Collaboration Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC JINST 16 (2021) P05014 CMS-EGM-17-001
2012.06888
63 M. Cacciari, G. P. Salam, and G. Soyez The anti-$ k_t $ jet clustering algorithm JHEP 04 (2008) 063 0802.1189
64 M. Cacciari, G. P. Salam, and G. Soyez FastJet User Manual EPJC 72 (2012) 1896 1111.6097
65 CMS Collaboration Jet algorithms performance in 13 TeV data CMS Physics Analysis Summary, 2017
CMS-PAS-JME-16-003
CMS-PAS-JME-16-003
66 CMS Collaboration Determination of Jet Energy Calibration and Transverse Momentum Resolution in CMS JINST 6 (2011) P11002 CMS-JME-10-011
1107.4277
67 E. Bols et al. Jet Flavour Classification Using DeepJet JINST 15 (2020) P12012 2008.10519
68 CMS Collaboration Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV JINST 13 (2018) P05011 CMS-BTV-16-002
1712.07158
69 CMS Collaboration Performance of the DeepJet b tagging algorithm using 41.9/fb of data from proton-proton collisions at 13 TeV with Phase 1 CMS detector CMS Detector Performance Note CMS-DP-2018-058, 2018
CDS
70 CMS Collaboration Performance of reconstruction and identification of $ \tau $ leptons decaying to hadrons and $ \nu_\tau $ in pp collisions at $ \sqrt{s}= $ 13 TeV JINST 13 (2018) P10005 CMS-TAU-16-003
1809.02816
71 CMS Collaboration Identification of hadronic tau lepton decays using a deep neural network JINST 17 (2022) P07023 CMS-TAU-20-001
2201.08458
72 CMS Collaboration Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13\,TeV using the CMS detector JINST 14 (2019) P07004 CMS-JME-17-001
1903.06078
73 J. Lever, M. Krzywinski, and N. Altman Principal component analysis Nature Methods 14 (2017) 641
74 CDF Collaboration Search for neutral Higgs bosons of the minimal supersymmetric standard model decaying to $ \tau $ pairs in $ \mathrm{p}\bar{\mathrm{p}} $ collisions at $ \sqrt{s} = $ 1.96 TeV PRL 96 (2006) 011802 hep-ex/0508051
75 L. Bianchini et al. Reconstruction of the Higgs mass in events with Higgs bosons decaying into a pair of tau leptons using matrix element technique NIM A 862 (2017) 54 1603.05910
76 P. D. Dauncey, M. Kenzie, N. Wardle, and G. J. Davies Handling uncertainties in background shapes: the discrete profiling method JINST 10 (2015) P04015 1408.6865
77 CMS Collaboration Observation of the diphoton decay of the Higgs boson and measurement of its properties EPJC 74 (2014) 3076 CMS-HIG-13-001
1407.0558
78 ATLAS, CMS Collaboration Combined Measurement of the Higgs Boson Mass in $ pp $ Collisions at $ \sqrt{s}= $ 7 and 8 TeV with the ATLAS and CMS Experiments PRL 114 (2015) 191803 1503.07589
79 CMS Collaboration An embedding technique to determine $ \tau\tau $ backgrounds in proton-proton collision data JINST 14 (2019) P06032 CMS-TAU-18-001
1903.01216
80 M. J. Oreglia A study of the reactions $ \psi^\prime \to \gamma \gamma \psi $ PhD thesis, Stanford University, . SLAC Report SLAC-R-236, 1980
link
81 T. Junk Confidence level computation for combining searches with small statistics NIM A 434 (1999) 435 hep-ex/9902006
82 A. L. Read Presentation of search results: The CL$ _{\text{s}} $ technique JPG 28 (2002) 2693
83 G. Cowan, K. Cranmer, E. Gross, and O. Vitells Asymptotic formulae for likelihood-based tests of new physics EPJC 71 (2011) 1554 1007.1727
84 U. Haisch, J. F. Kamenik, A. Malinauskas, and M. Spira Collider constraints on light pseudoscalars JHEP 03 (2018) 178 1802.02156
85 CMS Collaboration Precision luminosity measurement in proton-proton collisions at $ \sqrt{s} = $ 13 TeV in 2015 and 2016 at CMS EPJC 81 (2021) 800 CMS-LUM-17-003
2104.01927
86 CMS Collaboration CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s}= $ 13 TeV CMS Physics Analysis Summary, 2018
CMS-PAS-LUM-17-004
CMS-PAS-LUM-17-004
87 CMS Collaboration CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s}= $ 13 TeV CMS Physics Analysis Summary, 2019
CMS-PAS-LUM-18-002
CMS-PAS-LUM-18-002
88 CMS Collaboration Measurement of the inelastic proton-proton cross section at $ \sqrt{s}= $ 13 TeV JHEP 07 (2018) 161 CMS-FSQ-15-005
1802.02613
89 CMS Collaboration Performance of the CMS Level-1 trigger in proton-proton collisions at $ \sqrt{s} = $ 13\,TeV JINST 15 (2020) P10017 CMS-TRG-17-001
2006.10165
90 CMS Collaboration Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV no.~02, P0, 2017
JINST 12 (2017)
CMS-JME-13-004
1607.03663
91 CMS Collaboration Measurement of the Inclusive $ W $ and $ Z $ Production Cross Sections in $ pp $ Collisions at $ \sqrt{s}= $ 7 TeV JHEP 10 (2011) 132 CMS-EWK-10-005
1107.4789
92 CMS Collaboration Measurement of the inclusive and differential Higgs boson production cross sections in the decay mode to a pair of $ \tau $ leptons in pp collisions at $ \sqrt{s} = $ 13 TeV PRL 128 (2022) 081805 CMS-HIG-20-015
2107.11486
93 CMS Collaboration Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV JINST 10 (2015) P06005 CMS-EGM-13-001
1502.02701
94 R. J. Barlow and C. Beeston Fitting using finite Monte Carlo samples Comput. Phys. Commun. 77 (1993) 219
95 J. Butterworth et al. PDF4LHC recommendations for LHC Run II JPG 43 (2016) 023001 1510.03865
Compact Muon Solenoid
LHC, CERN